[[quoteright:194:[[VisualNovel/FateStayNight http://static.tvtropes.org/pmwiki/pub/images/swordlines2.png]]]]
Luminescent lines or gradients added by artists and animators to illustrate the speed and movement of a really fast swipe of a weapon. Only appearing occasionally in 2D games, they have become virtually ubiquitous during the 3D era. Usually comes in three primary varieties:
* A thin line added to the very tip of the blade. Most commonly used on lightweight, slender swords such as the katana or the jian.
* A wide encompassing arc that follows the entire blade. Often seen on heavy broadswords and {{BFS}}es.
* A mixture of the two: Multiple lines that perpendicularly follow the blade swing.

Note that Sword Lines aren't just limited to swords. Axes, sabres, staffs, clubs and even arrows have a high tendency to leave behind conspicuous lines which portray their path. Somewhat justified with {{Laser Blade}}s.

Arguably TruthInTelevision: Due to persistence of vision, after a sword is swung you can often see an arc.

A form of MotionBlur. Compare with SwordSparks. See also SwordBeam, in which the lines are turned into a deadly ranged attack. For ''guns'' that have this effect, see EveryBulletIsATracer. For when ''only'' the sword lines are shown in a possible GoryDiscretionShot, see TheHitFlash.
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!!Examples

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[[folder:Anime and manga]]
* The page image above: In ''VisualNovel/FateStayNight'' and ''LightNovel/FateZero'', Saber's sword has the special property "Invisible Air" that warps the air around it, making it invisible, so it can only be seen by the SwordLines it makes.
** Assassin's special ability, Tsubame Gaeshi, slices three times with one slash, making a highly stylized series of sword lines.
* ''Manga/DeathNote'' does this one with ''[[MundaneMadeAwesome pens.]]''
* Used in the [[TheFilmOfTheBook film adaptations]] of ''KaraNoKyoukai'' to illustrate the speed of the protagonist's knife attacks, but done sparingly, unlike AudibleSharpness.
* ''Anime/{{Karas}}'' makes full use of the trail effect to maximum potential.
* ''SamuraiChamploo'' pulls this off quite nicely, since its highly stylized look makes them appears like streaks of lightning.
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[[folder:Comic Books]]
* In ''{{Bone}}'', the Hooded One's scythe leaves a visible arc behind it when it's swung.
* Essentially, almost every time someone swings a blade in Western comics, you can expect this. Examples are numerous and include, but are certainly not limited to, {{Wolverine}} claw swipes or when ComicBook/ConanTheBarbarian swings his sword in the comic versions.
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[[folder:Film]]
* [[Film/VForVendetta V]]'s daggers do this in slow-motion.
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[[folder:Live Action TV]]
* This happens a lot in {{Tokusatsu}}.
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[[folder:Video Games]]
* The Cyborg Ninja's High Frequency Blade in ''VideoGame/MetalGearSolid'' (and VideoGame/MetalGearAcid) tend to leave a Type-2 trail.
* ''DevilMayCry''. The lines are usually transparent, but visible (Force Edge specifically disrupts the air when swung). And then there's Devil Trigger.
* Sword Lines are a graphical option in ''NeverwinterNights2''.
* Sword Lines are a constant in ''NinjaGaiden''.
* The ''SoulSeries'' has Type-2 trails that activate from the character's attacking weapon or limb, meaning punches, kicks, headbutts and other body attacks can leave trails too. The trail gains electric sparks during Guard Break attacks and starts burning during Unblockable attacks. Each character leaves a uniquely coloured trail, and this colour is customisable in Soulcalibur 5.
* Same for bladed weapons in ''SuperSmashBros. Melee'' and ''Brawl''.
** Marth's [[http://www.ssbwiki.com/Dancing_Blade Dancing Blade]] technique is a prime example of this trope, as the color of the blade's trail in ''Brawl'' is dependent on the input of the Control Stick/Directional Pad, with red being neutral/forward/side, blue being up, and green being down.
* ''SamuraiShodown'' goes here as well. Charlotte's version with her rapier treads into RazorWind territory, at least in the first games: the 'lines' drawn by her sword remain lethal even well past when they were 'drawn' by the tip of her sword.
* ''BattleForWesnoth'' uses these.
* They turn different colors depending on damage in ''{{Rune}}''
* Seen early on in ''Dark Vengeance''
* The cipher in ''VideoGame/{{Strider}}'' fills a sizable chunk of the screen with a crescent of light.
* ''VideoGame/CastlevaniaSymphonyOfTheNight''. One sword's line even has the word "verboten" written on it.
** A bizarre variant occurs in ''[[VideoGame/CastlevaniaPortraitOfRuin Portrait of Ruin]]'''s Sister mode. When using Stella, she hardly ever visibly swings her sword, but sword lines still appear and slice enemies.
* Zero in the ''VideoGame/MegaManX'' and ''VideoGame/MegaManZero'' series. His [[LaserBlade Z-Saber]] swings drew bright green arcs or sometimes exploded.
* The Beam Katanas from ''NoMoreHeroes''. But then, even Shinobu's sword leaves trails, and it's metal.
** It's assumed that all weapons are somehow beam-edged, so that they can block other beam-edged weapons. This includes: [[spoiler: Jeane's legs]]
* Sometimes used for rather strange things, like kicks and punches in ''{{Oni}}'', or snowboarding trick {{Combos}} in ''1080''.
* ''VideoGame/TheLegendOfZeldaOcarinaOfTime'' and ''TheLegendOfZeldaMajorasMask'' both have Link's swords leaving a trail that persist for a second or two after it has been swung.
** There are Gameshark codes for ''Ocarina'' that allow complete customization of the sword lines, from the color to the persistence.
** In some games when Link is at full health, he can fire a beam from his sword that looks like a Sword Line.
** ''[[VideoGame/TheLegendOfZeldaTheWindWaker The Wind Waker]]'' uses SwordLines. {{Cel-Shaded}} ones, which look exactly like on the concept-art.
* In ''FinalFantasyVII'', Sephiroth embodies this to a T. Even when he hasn't even swung it in a certain place, LINES STILL APPEAR. Now THAT is skill. The same thing goes for his attacks in ''Dissidia: Final Fantasy'', primarily his Octaslash.
** He did swing there. You just didn't see it.
* ''{{Warcraft}} III'' has very visible sword lines for heroes wielding any variety of non-magic weapon, as well as arrow lines for Night Elf archers.
* In ''WorldOfWarcraft'' many special attacks do this. ([[http://www.wowhead.com/spell=6572 Revenge]], for example.)
* Especially prevalent in ''DissidiaFinalFantasy'', where pretty much every character with a sword gets this effect one way or another. Special mention goes to the aforementioned Sephiroth, who seemingly produces multiple sword strikes from '''one swipe''' of his enormous sword.
** Sephiroth has been training with ''FateStayNight''[='s=] Assassin, obviously.
* Ezio's blades in ''VideoGame/AssassinsCreedII'' have the "line coming only from the tip because the blades are relatively slender" variant. There's a digitized aspect to the lines, which makes sense as all of Ezio's sequences take place in the Animus 2.0.
* Some melee weapons in VideoGame/Left4Dead2 do this, so that the animation is noticeable to the player while realistically fast.
* In ''MapleStory'', maxing out a Weapon Mastery skill changes the colour of the character's SwordLines to red for that kind of weapon.
* ''VideoGame/{{Touhou}}'' has a few examples, despite being a BulletHell {{Shmup}}: Konngara and Meira in the first two games would use their sword to draw lines, which dissolve into bullets a bit later. Youmu, from rather later in the series, did something kind of similar; her spellcards generally resulted in Sword Lines (which could last for quite some time...) and bullets coming from roughly the same area.
* Just about every weapon from the ''VideoGame/GodOfWar'' series has this, but the main offenders are the Blades Of Chaos/Athena/Exile, who start out as just having a small yellow-y trail a la the first kind, then get more spectacular (and [[TurnsRed more red]]) as they gain levels. By the final form, you're tossing around a rock concert's worth of glowy-ness. Sort of {{Justified|Trope}}, as all three kinds of blades are magic and are shown to be wreathed in magical flame-energy stuff when being used.
* In ''RagnarokOnline'', the Sorcerer skill Striking makes your weapon do this with red lines.
* ''VideoGame/MoonCrystal'' has it with the sword weapon you can have.
* ''SengokuBasara'' does this all the time, making for very flashy and colorful combat. Sometimes more justified than others.
* In AmericanMcGeesAlice, the Vorpal Blade leaves noticeable trail whenever it moves, even if Alice as much as runs with it.
* In Blade Of Darkness (''{{Severance}}'') special attacks are highlighted by a yellow trail behind the sword, and weapon-specials - with a red trail.
* This is ''all'' you see of your blade in ''VideoGame/FruitNinja''. You can even unlock trails with different colors and effects.
* The Gold Tracer in ''DarkSouls'' is the only weapon in the game with this sort of effect. This is intended, as it's used mesmerize the opponent as you stab them with the more discrete and venomous Dark Silver Tracer.
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[[folder:Webcomics]]
* Most weapon attacks in ''Webcomic/TheOrderOfTheStick'' are depicted with these.
* Used in [[http://www.sluggy.com/comics/archives/daily/041013 this]] ''SluggyFreelance'' strip. Though, in this case, they might simply be blood running off the blade.
* ''Webcomic/{{Homestuck}}''.
** At first it looks like [[http://mspaintadventures.com/?s=6&p=003482 Rose's knitting needles]] have done this, but [[SubvertedTrope it's actually purple yarn]].
** Jack however is fond of sword lines, often doubling as TheHitFlash.
* In ''Webcomic/DominicDeegan'' the title character learns to use these as a focus for his second sight in order to bypass scrying wards.
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[[folder:Western Animation]]
* ''WesternAnimation/AvatarTheLastAirbender'', taking inspiration from ''Anime/SamuraiChamploo'', has this in the fight between Zuko and Jet, which led some to believe that Zuko was using blue fire.
* Appears very prominently during Optimus Prime and Megatron's duel in episode 23 of ''WesternAnimation/TransformersPrime''. Notable, Prime and Megatron's respective Sword Lines are actually ''[[ColourCodedForYourConvenience colour-coded]]'', with the former's being blue and latter's being purple, matching the colours of their respective laser blasts as well.
** Not only laser blasts, Their eyes and even the Energon (Read: [[SymbolicBlood Blood]]) are also the same color.
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